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Stopping distances: speed and braking

The simple truth about speeding is: the faster you go, the longer it takes to stop and, if you crash, the harder the impact. Even small increases in speed could have severe consequences. If a pedestrian steps out into the path of an oncoming vehicle which is speeding the difference could be a matter of life or death.

In an emergency, the average driver takes about 1.5 seconds to react. Stopping  distances increase exponentially the faster you go.

How long it takes to stop driving an average family car

You can also access this infographic information in text form.

Speeding killed or injured almost 600 people in 2016

The stopping distances on the infograph are calculated based on the following assumptions:

  • In an emergency the average  driver takes approximately 1.5 seconds to react
  • A modern vehicle with good brakes and tyres, after braking, is capable of stopping at approximately 7 m/s2.
  • A dry road that is sealed and level enables good friction between the tyres and the road to help stop the vehicle sooner.  Scientifically, it has a coefficient of friction of approximately 1.
  • A wet road that is sealed and level has less friction between the tyres and the road which increases the stopping distance of a vehicle.  Scientifically, the coefficient of friction of approximately 0.7.

The stopping distances in the graph are generic and may be influenced by a number of driver, vehicle and environmental factors:

Driver factorsVehicle factorsEnvironmental factors
  • Attention
  • Vehicle age
  • Road surface
  • Fatigue
  • Type and condition of brakes
  • Road gradient
  • Impairment due to alcohol and drugs
  • Type and condition of  tyres, including tyre pressure
  • Road alignment
  • Vision issues
  • Safety features fitted to  the vehicle for example ABS, ESC, EBA, etc.
  • Weather conditions
  • Driver age and experience
  • Vehicle weight
 
  • Hazard perception ability
  • Towing a trailer or  carrying a heavy load